Heat exchanger with cooling fins

ABSTRACT

A heat exchanger comprises heat exchanging tubes ( 3 ) with a profiled inner and/or outer surface, which profiled surface provides at least one cooling fin. The heat exchanging tubes ( 3 ) may each be made of a helically wound profiled strip ( 4 ) with intermeshing profiled edges ( 5, 6 ), which perform both as cooling fins and reinforcement ribs of the tube, such that the heat exchanging capacity is increased and the wall thickness of the tube may be decreased and the heat exchanger will be more efficient and lighter than conventional heat exchangers with cylindrical heat exchanging tubes.

BACKGROUND OF THE INVENTION

The invention relates to an improved heat exchanger. OTC paper 17399 “Subsea Gas Compression—Challenges and Solutions” presented by R. Fantoft at the Offshore Technology Conference held in Houston, USA on 2-5 May 2005 and International patent applications WO03/033870, WO03/035335 and WO 2005/026497 disclose various types of heat exchangers that may be used in subsea natural gas and/or crude oil production facilities.

It is generally desirable to provide heat exchangers with heat exchanger tubes with a large inner and/or outer surface to enhance heat exchange between fluids in the interior and exterior of the heat exchanger tubes.

It is an object of the present invention to provide an improved heat exchanger with heat exchanger tubes with an enlarged inner and/or outer surface. The structural elements that are attached to the inner and/or outer surface have the following two benefits. (i) The heat excharger pipe can be made thinner for a given required design pressure, as the structural elements will provide structural strength. This reduces the heat resistance of the tube wall, thus increasing the heat transfer properties. (ii) The structural elements will increase the area for heat transfer, and heat will flow from the tube wall into the structural elements by conduction.

SUMMARY OF THE INVENTION

In accordance with the invention there is provided a heat exchanger comprising at least one heat exchanging tube with a profiled inner and/or outer surface, which profiled surface provides at least one cooling fin.

The use of heat exchanging tubes with a profiled inner and/or outer surface has the following two benefits.

I) The heat exchanging tubes can be made thinner for a given required design pressure, as the profiled surfaces will provide structural strength. This reduces the heat resistance of the tube wall, thus increasing the heat transfer properties; and

II) The profiled surfaces elements will provide cooling fins that increase the area for heat transfer, and heat will flow from the tube wall into the cooling fins by conduction.

Preferably each heat exchanger tube comprises one or more cooling fins which protrude in a substantially radial direction from the outer wall of each tube.

In a suitable embodiment a plurality of disk shaped cooling fins are arranged at the outer wall of each heat exchanger tube, which fins are distributed at substantially equal intervals along the length of each tube.

In a preferred embodiment each tube is provided with a helical cooling fin, which extends along at least part of the length of each tube.

In a particularly preferred embodiment each tube is made of a profiled strip which is helically wound such that adjacent strip sections at least partly overlap each other and such that the overlapping strip sections comprise intermeshing profiles that are clamped together and which profiles form the cooling helical cooling fin.

Preferably the profiled strip may be made of metal and the heat exchanger may comprise a plurality of heat exchanger tubes that are arranged substantially parallel to each other between a pair of fluid commingling conduits, that are often referred to as headers.

The profiled strip may have intermeshing profiled edges which dovetail into each other in the manner as disclosed in U.S. Pat. No. 6,516,833.

The heat exchanger may be installed at an underwater location and cooled by (sea)water surrounding the heat exchanger and may be a component of an underwater gas and/or crude oil assembly.

These and other features, embodiments and advantages of the heat exchanger according to the invention are described in the accompanying claims, abstract and the following detailed description of a preferred embodiment in which reference is made to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 depicts a schematic view of a heat exchanger provided with profiled heat exchanging tubes according to the invention;

FIG. 2 depicts in more detail a section of one of the profiled heat exchanging tubes of the heat exchanger shown in FIG. 1; and

FIG. 3 depicts in more detail a section of the profiled helical strip of which the profiled helical tube of FIGS. 1 and 2 is made.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 depicts a heat exchanger comprising a pair of fluid commingling conduits 1 and 2 between which a series of seven heat exchanging tubes 3 are arranged, which are each contain a profiled helical strip 4.

FIG. 3 shows that the profiled helical strip 4 comprises complementary profiled edges 5 and 6, such that the L-shaped profiled edge 6 of one section of the strip 4 fits into the U-shaped profiled edge 5 of an adjacent section of the strip 4, which partly overlaps said one section of the strip. The strip 4 may be made of metal and the L-shaped profiled edge 6 may be welded, brazed, glued and/or otherwise bonded to the U-shaped profiled edge 5 of the adjacent strip section.

FIG. 2 illustrates that the helically wound profiled strip provides a profiled heat exchanging tube 3 of which the outer surface has a helical profile formed by the outer surface of the helically wound U-shaped profiled edge 5. The U-shaped profile is inverted such that both ends of the U-shape are in contact with the heat exchanger tube.

It will be understood that the inner surface of the heat exchanging tube 3 may have a helical profile formed by the inner surface of the helically wound profiled edge 6.

It will further be understood that the helical profiled inner and outer surfaces will enhance the heat exchanging surface of the heat exchanging tube 3, such that the heat exchanger can be made more compact than conventional heat exchangers that are provided with substantially cylindrical heat exchanging tubes.

A further advantage of the use of profiled heat exchanging tubes 3 is that the helically profiled inner and outer surfaces not only provide cooling fins, but also reinforcement ribs, so that the wall thickness of the tubes 3 can be decreased, which further enhances the heat exchanging capacity of the heat exchanger, so that the heat exchanger will be more compact and lighter than conventional heat exchangers with cylindrical heat exchanging tubes.

The heat exchanger according to the invention is suitable to be used in any industrial application, in particular in subsea oil and/or gas production facilities or at topsides of offshore oil and/or production platforms. 

1. A heat exchanger comprising at least one heat exchanging tube with a profiled inner and/or outer surface, which profiled surface provides at least one cooling fin.
 2. The heat exchanger of claim 1, wherein each heat exchanger tube comprises one or more cooling fins which protrude in a substantially radial direction from the outer wall of each tube.
 3. The heat exchanger of claim 2, wherein a plurality of disk shaped cooling fins are arranged at the outer wall of each heat exchanger tube, which fins are distributed at substantially equal intervals along the length of each tube.
 4. The heat exchanger of claim 2, wherein each tube is provided with a helical cooling fin, which extends along at least part of the length of each tube.
 5. The heat exchanger of claim 4, wherein each tube is made of a profiled strip which is helically wound such that adjacent strip sections at least partly overlap each other and such that the overlapping strip sections comprise intermeshing profiles that are clamped together and which profiles form the helical cooling fin.
 6. The heat exchanger of claim 5, wherein the profiled strip is made of metal.
 7. The heat exchanger of claim 1, wherein the a plurality of heat exchanger tubes are arranged substantially parallel to each other between a pair of fluid commingling conduits.
 8. The heat exchanger of claim 1, wherein the heat exchanger is installed at an underwater location and is cooled by water surrounding the heat exchanger.
 9. The heat exchanger of claim 8, wherein the heat exchanger is a component of an underwater gas and/or crude oil assembly. 